The term Ambrosia beetle refers to a type of bark beetle/wood borer that borers into stems and branches of trees and introduces fungi. Many of the fungi introduced by Ambrosia beetles contribute to decline of the tree by impeding water movement through the xylem.

Most Ambrosia beetles that affect oaks and beech are secondary invaders of stressed trees. Ambrosia Beetles are attracted to trees with bleeding lesions, slime flux or other conditions that produce alcohols.